How would one distinguish a chromatid from a chromosome?

a) A chromatid is the portion of a chromosome on each side of its centromere.
b) A chromatid is the portion of a chromosome on each side of its kinetochore.
c) A chromatid is a twin of another chromatid resulting from chromosomal copying, both being joined at the centromere region.
d) A chromatid is a chromosome that has condensed into a DNA super coil prior to cell division, whereas a chromosome is uncondensed.
e) A chromatid is the structure at each end of a dividing cell that provides microtubules for moving chromosomes during cell division.